# ubelt.util_deprecate module

Currently this module provides one utility `ubelt.util_deprecate.schedule_deprecation()` which allows a developer to easily mark features in their libraries as deprecated.

ubelt.util_deprecate.schedule_deprecation(modname=None, name='?', type='?', migration='', deprecate=None, error=None, remove=None, warncls=<class 'DeprecationWarning'>, stacklevel=1)

  Raise a deprecation warning or error based on the version of a package.

  This helps provide users with a smoother transition by specifying a version when the deprecation warning will start, when it transitions into an error, and when the maintainers should remove the feature all together.

  This function provides a concise way to mark a feature as deprecated by providing a description of the deprecated feature, documentation on how to migrate away from the deprecated feature, and the versions that the feature is scheduled for deprecation and eventual removal. Based on the version of the library and the specified schedule this function will either do nothing, emit a warning, or raise an error with helpful messages for both users and developers.

  Parameters:

    - modname (str | None) – The name of the underlying module associated with the feature to be deprecated. The module must already be imported and have a passable `__version__` attribute. If unspecified, version info cannot be used.

    - name (str) – The name of the feature to deprecate. This is usually a function or argument name.

    - type (str) – A description of what the feature is. This is not a formal type, but rather a prose description: e.g. “argument to my_func”.

    - migration (str) – A description that lets users know what they should do instead of using the deprecated feature.

    - deprecate (str | None) – The version when the feature is officially deprecated and this function should start to emit a deprecation warning. Can also be the strings: “soon” or “now” if the timeline isnt perfectly defined.

    - error (str | None) – The version when the feature is officially no longer supported, and will start to raise a RuntimeError. Can also be the strings: “soon” or “now”.

    - remove (str | None) – The version when the feature is completely removed. An AssertionError will be raised if this function is still present reminding the developer to remove the feature (or extend the remove version). Can also be the strings: “soon” or “now”.

    - warncls (type) – This is the category of warning to use. Defaults to `DeprecationWarning`.

    - stacklevel (int) – The stacklevel can be used by wrapper functions to indicate where the warning is occurring.

  Returns:

    the constructed message

  Return type:

    str

  Note

  If deprecate, remove, or error is specified as “now” or a truthy value it will force that check to trigger immediately. If the value is “soon”, then the check will not trigger.

  Note

  The `DeprecationWarning` is not visible by default. https://docs.python.org/3/library/warnings.html

  Example

      >>> # xdoctest: +REQUIRES(module:packaging)
      >>> import ubelt as ub
      >>> import sys
      >>> import types
      >>> import pytest
      >>> dummy_module = sys.modules['dummy_module'] = types.ModuleType('dummy_module')
      >>> # When less than the deprecated version this does nothing
      >>> dummy_module.__version__ = '1.0.0'
      >>> ub.schedule_deprecation(
      ...     modname='dummy_module', name='myfunc', type='function',
      ...     migration='do something else',
      ...     deprecate='1.1.0', error='1.2.0', remove='1.3.0')
      >>> # But when the module version increases above the threshold,
      >>> # the warning is raised.
      >>> dummy_module.__version__ = '1.1.0'
      >>> with pytest.warns(DeprecationWarning):
      ...     msg = ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else',
      ...         deprecate='1.1.0', error='1.2.0', remove='1.3.0')
      >>> print(msg)
      The "myfunc" function was deprecated in dummy_module 1.1.0, will cause
      an error in dummy_module 1.2.0 and will be removed in dummy_module
      1.3.0. The current dummy_module version is 1.1.0. do something else

  Example

      >>> # xdoctest: +REQUIRES(module:packaging)
      >>> # Demo the various cases
      >>> import ubelt as ub
      >>> import sys
      >>> import types
      >>> import pytest
      >>> dummy_module = sys.modules['dummy_module'] = types.ModuleType('dummy_module')
      >>> # When less than the deprecated version this does nothing
      >>> dummy_module.__version__ = '1.1.0'
      >>> # Now this raises warning
      >>> with pytest.warns(DeprecationWarning):
      ...     dummy_module.__version__ = '1.1.0'
      ...     ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else',
      ...         deprecate='1.1.0', error='1.2.0', remove='1.3.0')
      >>> # Now this raises an error for the user
      >>> with pytest.raises(RuntimeError):
      ...     dummy_module.__version__ = '1.2.0'
      ...     ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else',
      ...         deprecate='1.1.0', error='1.2.0', remove='1.3.0')
      >>> # Now this raises an error for the developer
      >>> with pytest.raises(AssertionError):
      ...     dummy_module.__version__ = '1.3.0'
      ...     ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else',
      ...         deprecate='1.1.0', error='1.2.0', remove='1.3.0')
      >>> # When no versions are specified, it simply emits the warning
      >>> with pytest.warns(DeprecationWarning):
      ...     dummy_module.__version__ = '1.1.0'
      ...     ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else')
      >>> # Test with soon / now
      >>> with pytest.warns(Warning):
      ...     ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else',
      ...         deprecate='now', error='soon', remove='soon', warncls=Warning)
      >>> # Test with truthy values
      >>> with pytest.raises(RuntimeError):
      ...     ub.schedule_deprecation(
      ...         'dummy_module', 'myfunc', 'function', 'do something else',
      ...         deprecate=True, error=1, remove=False)
      >>> # Test with No module
      >>> with pytest.warns(Warning):
      ...     ub.schedule_deprecation(
      ...         None, 'myfunc', 'function', 'do something else',
      ...         deprecate='now', error='soon', remove='soon', warncls=Warning)
      >>> # Test with No module
      >>> with pytest.warns(Warning):
      ...     ub.schedule_deprecation(
      ...         None, 'myfunc', 'function', 'do something else',
      ...         deprecate='now', error='2.0.0', remove='soon', warncls=Warning)